1. Field of the Invention
This invention relates to a reconfigurable integrated circuit device, and in particular to a reconfigurable integrated circuit device which automatically configures an initialization circuit to initialize internal or external memory when power is turned on.
2. Description of the Related Art
A reconfigurable integrated circuit device has a plurality of processor elements and a network which connects processor elements, and configures the processor elements and network into an arbitrary computation state or computation circuit based on configuration data output by a sequencer in response to an external or internal event.
Programmable microprocessors of the prior art generally read instructions stored in memory and process the instructions sequentially. Hence the number of instructions which can be executed simultaneously by a single microprocessor is limited, and there are limits to the processing capacity.
On the other hand, the above reconfigurable integrated circuit device is provided with a plurality of different types of processor elements, such as an ALU having adder, multiplier, comparator and other functions, and a delay circuit or counter, and in addition a network connecting the processor elements is provided, so that the processor elements and network are reconfigured into a desired configuration based on configuration data from a state transition control section comprising sequencer, and prescribed computations are executed in this computation state. A plurality of computation circuits are configured in advance by a plurality of processor elements, so that the computation circuits can perform data processing simultaneously. And, when a data processing is completed in one state, other configuration data can be used to configure another computation state, and a different data processing can be performed in that state.
In this way, a reconfigurable integrated circuit device can dynamically reconfigure different computation states, so that data processing performance for large volumes of data is improved, and overall processing efficiency can be enhanced. Reconfigurable integrated circuit devices are for example described in Japanese Patent Laid-open No. 2001-312481.
In general, integrated circuit devices execute various initialization processing when power is turned on, and after initialization processing ends an internal reset is cancelled, and normal operation is performed. Initialization processing at the time power is turned on may include, for example, operation to initialize a PLL circuit which generates an internal clock in sync with an external clock, initialization of registers in which various parameters are set, and data downloading. In a reconfigurable integrated circuit device also, initialization processing must similarly be performed when power is turned on, and a circuit must be provided in advance for this initialization processing. Or, when the CPU executes an initialization program, the initialization program must be provided in advance in program memory.
However, a circuit to perform this initialization processing operates only during a fixed interval at the time power is turned on, and in normal operation after the internal reset is cancelled may no longer be necessary. Hence the provision of such a circuit for initialization processing separately from a reconfigurable circuit results in a larger circuit scale, and is undesirable. Similarly in the case of an initialization program, the program volume is increased, which is undesirable.
Further, internal memory is incorporated within integrated circuit devices, and external memory is connected externally. When a reconfigurable circuit unit is incorporated, the reconfigurable circuit unit also has a memory element. Hence numerous processes are required in order to initialize the data within this plurality of memory elements.